The invention relates to a rail wheel having a wheel disk made of a plastic material and a tire made of metal. The two are connected with one another using a metallic intermediate ring onto which the tire is shrunk.
In the case of such a rail wheel, as for conventional rail vehicle wheels having an all-metal construction, it is naturally desirable to be able to exchange the tire after a certain amount of wear of its running tread and of the wheel flange. The use of the metallic intermediate ring provided for facilitating an exchange of the tire in the case of a rail wheel as is known from German Patent document DE-PS 31 43 845 has the advantage that the tire can be shrunk on in a conventional manner. However, the connection selected for this metallic intermediate ring with the wheel disk, by way of a radial ring extension embedded therein as the carrier of anchoring devices, apart from the expenditure of such a form-locking "embedding" connection, has the considerable disadvantage that the intermediate ring must be integrated during the manufacturing of the wheel disk, thus together with its shaping. As a result, for example, during the normally applied wet-winding of the wheel disk, an extremely precise positioning of the intermediate ring with respect to the wheel hub is required.
It is therefore an object of the present invention to eliminate the embedded connection between the wheel disk and the intermediate ring in the case of a rail wheel of the above-mentioned type while not reducing the safety of their connection when stressed by axial forces.
This object is achieved according to the present invention by a rail wheel having a wheel disk made of a plastic material and a tire made of metal. The two are connected with one another using a metallic intermediate ring onto which the tire is shrink. The wheel disk has a conical cross-sectional profile on its circumference. The intermediate ring, which is form-locking therewith, is axially divided into two partial rings. The two partial rings have corresponding partially conical interior surfaces which are in a mutual force-locking connection and are glued to the wheel disk.
It is an advantage of the present invention basically that the connection of the intermediate ring with the wheel disk no longer plays a role during its manufacturing. To the contrary, for the transmission of the axial forces from the intermediate ring to the wheel disk, two load paths are made available; that is, a double safety connection is ensured. Thus, the force can be transmitted by way of the glued, relatively large-surface connection between the intermediate ring or its partial rings and the wheel disk.
In this case, when shearing strains occur, the conical form of the interior surface of the intermediate ring will have compressive strains in the glue and therefore result in a significant increase of the stability under load of the glued connection to the wheel disk in the shearing direction. On the other hand, in the case of a failure of the glued connection, the transmission of the axial forces can take place by way of the form-locking conical surfaces of the intermediate ring and the wheel disk. With respect to this case, a further embodiment of the intermediate ring forming an axial mounting of the wheel disk on its hub will still increase the effectiveness of the load path.
Naturally, for obtaining the same effects in the two possible directions of the effect of the axial force, it is recommended that, if possible, a center division of the intermediate ring be selected, that is, a division in the wheel plane into two identical partial rings with a semiconical interior surface. As an alternative, depending on the demands on the rail wheel, instead of such a center division, an eccentric division is also conceivable, for example, a so-called side division of the intermediate ring.
Furthermore, according to a further embodiment of the invention, the wheel disk has a conical cross-sectional profile also on the hub side and is connected with a metal axle shaft by means of an additional intermediate ring. The additional intermediate ring is made of metal and is force-locked with the cross-sectional profile. The additional ring is divided into two additional partial rings of a partially conical outer surface which corresponds to the wheel disk hub. The additional partial rings are in a force-locking connection with one another and are glued to the wheel disk. The above-mentioned advantages of the double safety connection can also be utilized for the connection of the wheel disk with an axle shaft.
It is a further advantage of the present invention that the expenditure for the exact positioning of the respective intermediate ring on the wheel disk is relatively low. In this case, it is not important whether the wheel disk or its plastic structure is already hardened, is partially hardened, or is not yet hardened during the positioning of the intermediate ring. In the latter case, the unhardened plastic may expediently be used as the glue of the glued connection. In this case, the two partial rings bound a groove on their point of contact above a cone point of the wheel disk. This permits the accumulation of excess plastic material, i.e., glue and therefore also prevents a fold formation on the surface of the unhardened wheel disk when the partial rings are pushed on.
Finally, with respect to the force-locking connection of the two partial rings with one another, it should be noted that these partial rings when screwed together basically must only secure the cohesion of the partial rings during the exchange of the tire because otherwise the shrunk-on tire will ensure a sufficiently stressable force-locking mutual connection of the partial rings. This is particularly true in the case of a so-called glued shrinking during which the tire is additionally glued to the intermediate ring.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.